that's true but if you think about it he only recently got the memories so he is a different person because he probably hasn't experienced everything he experienced in his past life.
True true
Imo, the current emperor needs to thank the past wonje for his change. As bad as the past wonje was, he actually learned something at the very end when it was all too late. That regret & sadness, & the sin from the brutal killing rampage he went on just to earn himself a second shot at a new life with Heun, they all left a deep & lasting impression on his current self. He's finally starting to understand the one thing that he couldn't grasp in the past life, which is the root cause of his brutality: the concept of pain. He is now willing to learn so as not to follow in the same horrible footsteps. So him flipping 180 degrees in attitude is something that can be attributed to him learning from the past. This will be made clear in the next few episodes.
I kind of thought of something similar to what you said while reading the last chapter when he allowed Heun to slap him and rage at him. The way he worded certain things were as if he was saying he’s learning and trying to change himself and do what he wasn’t able to do in the past.
I like how it’s as if he’s like not even the same person, like has a completely different soul, it’s as if he’s a whole different person mentally and the old him actually died. As if he was a person reincarnated into that body he’s in with that person’s memories. Those are the vibes I’m getting from him and I like it. Everytime there’s a flashback I kind of get annoyed seeing him because like it said it’s like he’s a new person in the present and the past is like a different being. Present him makes me comfortable though.